It can be produced by starting on a high note and playing the fourth below or by starting on a low note and playing the fourth above.

A perfect fourth in just intonation most often corresponds to a pitch ratio of 3:4 or 1:1.333..., or various other ratios, while in an equal tempered tuning, a perfect fourth is equal to five semitones, a ratio of 1:25/12 (approximately 1:1.3348), or 500 cents, about 1.955 cents wide.